Articles about diseases

Archive for the ‘Diagnostic’ Category

The impact of soy consumption on breast cancer prevention and treatment is not clear although many women believe soy supplementation is beneficial based primarily on results from epidemiological studies. Moshe Shike, M.D., from the Department of Medicine at Memorial Sloan-Kettering Cancer Center and Weill Cornell Medical College in New York, NY, and colleagues conducted a randomized placebo-controlled study of the effects of soy supplementation on gene expression and markers of breast cancer risk among women diagnosed with invasive breast cancer. The study, run between 2003 and 2007 at Memorial Sloan-Kettering, enrolled a total of 140 patients who were randomized to either soy supplementation (soy protein) or placebo (milk protein), which lasted from the initial surgical consultation to the day before surgery (range=7-30 days). Tumor tissues from the diagnostic biopsy (pre-treatment) and at the time of resection (post-treatment) were then analyzed. They observed changes in several genes that promote cell cycle progression and cell proliferation among women in the soy group.

The authors conclude, “These data raise concern that soy may exert a stimulating effect on breast cancer in a subset of women.”

In an accompanying editorial, V. Craig Jordan, O.B.E., D.Sc., Ph.D., FMedSci, from the Department of Oncology at the Georgetown University Lombardi Comprehensive Cancer Center, Washington, DC, discusses how timing of soy supplementation is critical and reviews the evidence in the literature on phytoestrogens, which are contained in soy, and their known action in breast cancer. He writes, the study by Shike et al. “…illustrates the dangers of phytoestrogen consumption too soon, around menopause, but the biology of estrogen in estrogen-deprived conditions suggests that phytoestrogen could have benefit a decade after menopause.” He cautions that appropriate doses of soy and timing of consumption are critical considerations.

Severely ill prostate cancer patients are helping researchers test a diagnostic tool that involves injecting a radioactive substance into their bodies. Norway has the fifth highest mortality rate for prostate cancer in Europe.

Four doses of a radioactive tracer called 18F- FACBC are on their way from Oslo to Trondheim in a private jet. Three NTNU researchers, one doctor, two radiographers and a bioengineer fidget nervously as they wait. They check the time.

The plane cannot be delayed. Today is a bad day for fog to descend around Oslo’s main airport, Gardermoen, or for there to be a traffic jam between the Trondheim airport and the city hospital, St. Olavs. Everything has to be on time.

Radioactive decay

From the second that 18F- FACBC is injected into its container, it begins to degrade. In 110 minutes, half of the radioactive substance is gone. If the plane is delayed too much, there won’t be any radioactivity left for the last patient. Then more doses have to be flown up from Oslo.

Now the plane is 20 minutes late. Time really is money when it comes to this radioactive substance. One dose costs NOK 30 000 (3700 Euros). The first patient is already on the table, ready for the procedure. He has an aggressive form of prostate cancer. Doctors fear that it has spread to his lymph nodes.

Now he is waiting to be examined with the most advanced imaging technology that can be found in Norway, a combined PET MRI scan with a price tag of NOK 50 million. He will have to lie still in what boils down to a tiny cave for over an hour while the machine scans and makes images of his blood, bones, and cancer cells.

Finding its way through the body

But this kind of advanced imaging requires a radioactive tracer. With its short half-life, 18F- FACBC (which is an abbreviation for 1-amino-3-fluorine 18-fluorocyclobutane-1-carboxylic acid) has just the right characteristics for the job.

The medical team works quickly when the doses finally arrive at the hospital.

Fortunately, the timing is perfect. First the patient is given an injection of the tracer in his arm, and then placed into the machine, where the tracer finds its way into his veins.

For the radioactive substance to find its way into cancer cells, it needs to have a carrier, a kind of pilot that is able to lead the way to the tumours. In this case, an amino acid acts as the carrier. This is because of cancer cells’ appetite for certain amino acids. A cancer cell is much more active than other cells. It needs more building blocks than other cells, more food. As a result, it attracts and absorbs the amino acid that has been injected into the body.

The radioactive tracer is picked up by detectors that are placed in a ring around the patient in the scanner, and the machine makes images of the cancer cells that light up from the tracer. At the same time, MRI photos of the area are taken, so that doctors get a unique package of information to help them determine which type of treatment is appropriate.

Eight private jets

After an hour, the scan is over and the patient is backed out of the PET MRI. A day later, all of the radioactivity will have left his body. In a few days, he will be in surgery. Hopefully, he has a number of healthy years left to live.

It will take a few years, however, before researchers will be able to conclude how PET MRI scans can be used to improve the diagnosis and treatment of prostate cancer. First, they need to conduct their study with 32 patients. Eight private jets of radioactive tracer will need to be flown to Trondheim, at a cost of NOK 960 000 for this substance.

Shorter, less surgery

This is the first research study in the world where amino acids and PET MRI are being used to try to improve the diagnosis of prostate cancer.[faktaboks=”1″ stillopp=”hoyre” storrelse=”liten”/]

Currently, doctors remove the lymph nodes found in the pelvis of patients with aggressive prostate cancer, without really knowing if it is necessary. Only by cutting into the lymph nodes after they have been removed can doctors determine if the cancer had actually spread.

The NTNU researchers’ goal is for PET MRI to be able to do this detective work before the patient has to undergo surgery, so that surgeons know whether or not removing a patient’s lymph nodes is actually necessary. As a result, some patients should be able to have shorter, less involved surgery, which means less side effects and potential complications.

Diagnoses and the answer key

Researcher will go through the images of all 32 study participants, and then compare these images to their “answer key,” which in this case are the lymph nodes that were removed and biopsied from the patients. Comparing the nodes with the PET MRI images will show whether or not the scans can be used to help in the diagnosis of prostate cancer.

Endoscopic biopsy of the lymph nodes is a minimally invasive, non-surgical intervention that has recently begun to be used to stage lung cancer. The study conducted by Dr. Liberman’s team involved 166 patients with confirmed or suspected non small cell lung cancer, and was designed to compare the new approach to surgical staging under general anesthesia, as prescribed in current guidelines for this type of cancer. The findings, which were recently published in CHEST Journal, the official publication of the American College of Chest Physicians, show that the endoscopy approach is not only sensitive and accurate, but also leads to improved staging compared to surgical staging due to its ability to biopsy lymph nodes and metastases not attainable with surgical techniques.

Research protocol

All patients underwent endobronchial ultrasound (EBUS), endoscopic ultrasound (EUS) and surgical mediastinal staging (SMS) during a single procedure. Each subject served as his or her own control. The results of the EBUS, EUS and combined EBUS/EUS were compared to SMS (gold standard) results and, in patients with negative lymph node staging, to lymph node sampling at pulmonary resection.